Power source (constant voltage / DC) Provides stable electric arc to melt wire and base metal. If power swings widely, weld quality suffers.
Wire-feed unit + consumable electrode wire Continuously feeds metal filler; simpler than replacing rods often (like with stick welding). Speeds up work and allows long seams.
Welding gun / torch with contact tip and gas nozzle Delivers wire, electricity, and shielding gas precisely to weld area — critical for arc stability and weld quality.
Shielding gas supply (e.g. inert gas or gas mixture) Protects molten weld pool from oxygen and moisture, preventing contamination, porosity, weak welds.
Controls for voltage/current, wire feed speed, gas flow Let you set parameters based on metal type, thickness, and job — wrong settings cause poor welds, spatter, weak bonds